Mechanical properties and constitutive model of a composite solid propellant under the synergistic effects of accelerated aging time, pre-strain, and damage growth

Abstract In this study, a systematic experimental program was conducted to understand the stress−strain behavior of a composite solid propellant after different accelerated aging times (30–120 days) with different pre-strains (0%–15%). The effects of accelerated aging time and pre-strain during aging on the mechanical behavior of the propellant were analyzed. The pre-strain effect on the microstructure was observed by a scanning electron microscope to demonstrate the pre-strain dependence of the mechanical behavior of the propellant. The microscopic variation with pseudo-strain was also detected by an optical microscope to analyze the damage process of the propellant. The effects of accelerated aging time and pre-strain on the damage growth were discussed. Finally, a constitutive model was proposed, considering the synergistic effects of viscoelasticity, accelerated aging time, pre-strain during aging, and damage growth. The calibrated model accurately predicted the stress-strain behavior of the composite solid propellant after different accelerated aging times with different pre-strains.